Cluster of whooping cough breaks out in Wellington Tuesday, 10 January 2017

Source: Stuff, 6 January 2017

An illness dubbed the "100-day cough" is infecting some adults who have  had a full dose of vaccinations.

Whooping cough can be deadly in young babies and, while the symptoms are less severe in adults, the hacking cough, vomiting, and tiredness can be debilitating.

Medical officer of health Stephen Palmer said there were 15 confirmed cases in Karori between December 10 and December 23. Two of those were adults, one was a 13-year-old, one was 14, and the rest were aged between three and 11.

Nine of those affected were from Karori Normal School, where parents were sent a notice.

"Regional Public Health has had several notifications recently of confirmed cases of whooping cough (pertussis) in adults and children," the notice said.

"The bacteria are circulating in the community, which potentially can put young babies and small children at risk of this highly infectious disease.

"In children under one year of age, this can be very serious. Women in the last four weeks of pregnancy are advised to see their GP or lead maternity carer."

The Dominion Post is aware of one other diagnosed case in an adult outside Karori who was initially misdiagnosed before being told she had whooping cough. She also developed pneumonia and suffered vomiting, tiredness, and a persistent cough lasting two months and counting.

Palmer said immunisation was effective in stopping whooping cough, but it wore off as people got older, "more so than the other ones you are immunised for".

Those most at-risk were middle-aged adults who were around young children, and they should consider getting a booster shot, he said. "Kids have caught it from adults, then spread it."

Doctors were supposed to notify Regional Public Health if they suspected cases, but a laboratory test  from a throat swab was needed to confirm a diagnosis, and laboratories also notified confirmed cases.

Karori Medical Centre GP Jeff Lowe said whooping cough levels in the community had been high for a "number of years".

"The important thing is people remain vigilant so we can stop the spread."

In April 2016, Starship paediatric doctor Fiona Miles warned New Zealand was in line for a whooping cough epidemic.

Whooping cough was always present in the community, but tended to work on a four-year cycle. A doubling of cases, and a big surge in Australian cases, meant an epidemic was highly likely, she said.

Up to 70 per cent of babies aged under one who caught whooping cough would end up in hospital. About one in 100 would die.

"We lose about one a year. This is a preventable disease so we shouldn't be losing anyone, " Miles said.

There had been some success in getting mothers and grandparents immunised, but more needed to be done to make fathers realise they also posed a risk.

She said most whooping cough deaths were babies who were too young to be vaccinated, making it important for parents and caregivers to be vaccinated so they did not pass on the illness.

"We have had some where the parents have chosen not to vaccinate [their children] and they very much regret it when they see their children struggling to breathe, or dying."

The Ministry of Health said whooping cough was most likely to kill in the first year of life, and infants continued to die from it despite state-of-the-art intensive care.

"It is estimated that in the developed world three times more deaths are due to pertussis than are reported."

WHAT IS WHOOPING COUGH?

Whooping cough, or pertussis, is a common and potentially deadly childhood illness caused by the bacterium Bordetella pertussis.

Whooping cough is usually characterised by a cough lasting longer than two weeks with spasms of coughing ending in vomiting or difficulty breathing. This is often accompanied by a whooping sound. Adults can also get whooping cough but usually do not have the classical whooping and vomiting after bouts of coughing.

The incubation period is between six and 20 days, average is 14 days. Whooping cough may start with a runny nose which then proceeds to coughing. 

The pertussis vaccine doesn't last forever, so people who haven't been immunised since they were children have low immunity and if there's an outbreak then it's easy for it to be transmitted on.

Whooping cough vaccines should be done at six weeks, three months and five months of age.

The vaccination is funded for all children and is also free for pregnant women between 28-38 weeks.